Telephone-exchange system



, Jul 10, 1923. 1,461,221

L. A. MORTIMER TELEPHONE EXCHANGE SYSTEM Q Filed Nov 19, 1920 100/3 4. Morf/mer aRMW L Patented July 10, 19:23; i

LOUISA. lvronrimnnjornnw'YoRKi. 'N'. Y" aselenoaro wns 'rnanfnnneritrc 05M. PANY, mconronarnnor vnw YORK,

N. .Y.. A conrozaiisrion o.F new Yoiun;

} j'r LErHONE- X HANGE SYSTEM. g

Application filed'November 19,.19aof. seria1-1 r 425,o7s. i

T 0 all whom z't may] concern: i I

Be it known that I, LOUIS A. BTORTIMEIQ, a citizen of theUnited States, residing, at New York, in the county of New" YTJIk, State of New York,'have invented certain new and useful Improvements ,in Tele-. phone Exchange .Systemsyof which the following is a full, clear, concise, and exact.

description. I I

This invention relates to telephone exchange systems and 'more particularly to improved signaling arrangements.- for link circuits used in such systems.

It is an object of this lnventionto provide for a link circuit which is'used to extend a connection froma cord circuit associated with one switchboard'to a cord circuit of another switchboard, new andv im proved means for automatically causln'g' the disconnection of ringing current fromfthe cord circuit. immediately upon' the, actuation of the, signaling device at the incoming end of the link circuit; Previously, itgwas' necessary to maintain the ringing response relay in verycareful adjustment so'asto cause a reliable operation of the tripping relay in the cord circuit and the consequent disconnection of the ringing current.

To attain this object in accordance with afeature of 'thisinventio'n, a ringing re-. sponse relay in a linkj'circuit is made to control a second relay'which' connects across. the line a tripping bridge momentarily but positively so as to cause a reliable disconnection of the ringing current.

This object is further attained in accordance with another feature of the inventionby arranging a ringing response 'relay' so that uponits complete operation its w ndins is included in a circuit offlowerimpedance than that in which it-was before it begins to respond. This increases the reliability of the operation'of the relay since it compensates for the shunting away of current through the tripping bridge cons nected'across'the'circuit.

The invention will be understood-from the following specification and accompanying drawing in" which the figure shows a subscribers station 27 connected to a line circuit A terminating at a switchboard fromwhich aconnection may 'be ente'nded -lo 'means' of a cord circuitB andhnk cir .cuit G,- to a cord circuit; D at another I i switchboard, to which cord circuit 'a'telephone32 is connected.:--Although the fig 1:

.ure shows ;only onesubscribers line circuit, one cord 'circuitand one link cirouiig'it' will be. understoodthat there maybe ,a'plural-j' city offeach of these, each. similarJto those 0] shown. The cord circuitBisarranged so thatwhen th plug 1. is inserted 'int 'the v ack-.2,ra ringingqresponse relay 3 operates from asource of grounded ringing'current 19 associated wlth cord circuit B and throu h thecontacts 'of a. ringing relay 5 over. the conductors 'oflinkcirc'uitiCfl The Op i n fifelayB causes the illuminationm l p of az lamp' 4,1 the operation of aflmarginal .tripplng relay 16, and consequently the release of relay- '5 and the discontinuance of ringing current: The operator in-control of the cord. c1r'cu1t;D responds tothe illumination of lampa- :by'i-inserting a-plug6 into a jack? thereby extinguishing lampll.

" It is thought'thatthe: invention willbe more :fully understood from the following 1 i Y T description'.

W1 en the freceivcr at the subscribers sta-- tion 2 is removed-fromthe switch hookto response thereto, the operator incontrol-of so I v 'initiateza call, a lamp Eli s lighted in response to the" usual operationdf linerela-y In:

the' line relay 30landextinguishthe lamp 8. :Relayf 11" operates and" prevents the. illue a part'of this invention andare shown only -,minationof'the-supervisory lamp 12. ,-;Since, 7

these circuits are wellfknown, and areanot .90

to givea more complete description,'details .of'operation are not 'given'." fThe operator set of theusu'al type j,( not shown) L Upon in answering actuates .thelisteningfkey 113. j and connectstothe cord circuit ajftelephonem 27 desiresa connection'tobe[extended tothe switchboard" with which a is associated v the-- cord circuit-'D,'the operator inserts plug-l "into jack 2. Relays 5 and-1 L are-then operated" over the following 'path'i,v from,

grounded battery through the winding of.

relay]. 5 normal contacts of relaysila and 16, supervisory lamp 17 sleeve contacts ofplug'l and ack ,2, and winding of relay 14;

to ground.- Relay 114;; operating discona nects, at its normal contacts, the windings of relay 18 from the conductors of link circuit C to which conductors relay 5 in operating connects ringing current and causes the actuation of the ringing response relay 3 over the following circuit: from the source of grounded ringing current 19 through the winding of marginal relay 16, lower alternate contact of relay 5, ring contacts .015

plug 1 and jack 2, lower left-hand winding of repeating coil 24, normal contact of relay.

21, condenser 20, winding of relay 3,upper ing interval representedis a major part of the ringing period. .It the time interval of this change in impedance is not of sufficient duration to operate relay 16 at this time, said relay will be operated during the next ringing period in a manner hereinafter described. Relay' 3 in operating causes the operation of relay 21, and of lamp 4 through obvious circuits. Relay 21 in operating locks up through the following circuit:

from grounded battery through the normal contact of relay 22, right-hand alternate contact of relay 21, and winding relay to ground. Accordingly, av momentary operation of relay Bsuiiices to cause a steady illumination of the lamp & through the following circuit: from grounded battery through the normal contact of relay 22, right-hand alternate contact of relay 21 and lamp 4 to ground. "The left-hand contacts of relay 21 areiot' the make-betore-break type and are designed so that the alternate contact is closed before the normal contact is broken. Accordingly, relay 21 in operating, at the instant when all the left-hand contacts are together, momentarily bridgesthe resistance 23 across the tip and ring conductorsof the link circuit C over the following path: from the tip conductor through resistance 23, the make-betore-break contacts of relay 21 and-thence in parallel. one

path extending through the left hand con tacts of relay 3 to the ring conductor and the other path extending through'the lower left-hand winding of. repeating coil'24i to the ring conductor. The circuit through the lower left winding of the repeating coil is only momentary because when relay 21 is completely operated, the circuit through the repeating coil is broken at the normal contact of relay 21, A soon as relay 21 is completely operated, and while relay 3 is still operated, the resistance-23 is also inoi'nentarily bridged across the conductors of the link circuit through the left-hand contact of relay 3, which increases the -eliabiL ity of such tripping connection. p

The resistance 23 being connecter de scribed above, relay 16 now operates over the circuit previously traced for relay 3, but which now includes the resistance 28 of low impedance, connected across the con ductors as described above. Relay 16 by its operation removes theshort circuit from the winding, of relay 15 which operates and.

short-circuits the winding of relay 5, causing its release, and disconnecting ringing current from cord circuit The operator in control of the link circuit D observes the illumination of lamps and inscrtsplug 6 into jack 7 establishing a:

tinguishes the lamp 4. Relay 22 connects i across the link circuit through its alternate contact,.-the resistance 31 which causes'the operation of supervisory relay 25 orer the following circuit: from grounded battery through the winding of relay 25, lower nor- 4 mal contact of relay'o, ring contacts or" plug 1 andjack 2, lower left hand winding ot repeating coil 24, resistance 31,- alternate contact oi. relay 22, upper left hand wind ing of repeater coil 2 1,"ti 1contacts=ot jack 2 and plug 1 andi'ipper normal contact of relay 5 to ground. places the shunt resistance 26 around the Relay 25 in operating ins supcrrisory lamp 17, which e'xtinguishes it, notifying the operator in control of the cord I circuit B that the call has been answered. When the conversation is completed. plug 6 is withdrawn from, jack 7', which releases relay 22 and opens the bridge circuitincluding resistance 31, causing the release of supeiwisory relay 25 and the consequent illumination of lamp 1?. In the usual manner the restoration of the receiver station 27' causes the illumination of lamp .12. The operator in control of the cord circuit observingthe illumination of both lamps, Withdraws plugs 9 and 1, the sleeve relays release andall apparatus is now restored to normal.

The link circuit C is so arranged that the operator in control of cord circuit D may initiate a call and have the connection exitendedby the operator in control of cord circuit B to the subscribers station 27. This is accomplished by the insertion of plug 6 into jack 7 operatingover the circuit pie 1 g; acrossthe link conductors resistance 31- to operate the relay 18 and illuminate the viously traced therefonrelay 22 and bridgf L re-1,221

lamp 28. Cord circuit Bis then used, to extend'in the regular way, the connection to station 27. r i 9 7 What is claimedfis 1. In a telephone exchange system, a subscribers cord circuit, a source otringing current,a s itchboard, a link circuit forextending'a connectionfrom said cord circuit to said switchboard, a 'signaling device associated'i with the link :ci'rcu-it, meansior'c'onnecting such ringing current source to the" link circuit, means responsive to the ring.- lng current to operate said signaling device,

additional means in the "link "circuit also responsive to suclrringing current to cause adis'connectionofthe source, and means for maintaining an operative c1rcu1t for said.

additional means independently oftheringing current. i

2. In a telephone exchange system, a sub-- scribers cord circuit, a source of ringmg current, a switchboard, a link circuit for extending a connection from said cordrcircuit to said switchboard, a signaling device associated with the link circuit, means for com necting said source to the link circuit, means comprising a relay responsive to the ringing current tooperate .said signaling device,

another relay in the link circuit responsive to the ringing current to cause a disconnection of the source, and means for maintaining an operative circuit for said second mentioned relay until the ringing current is disconnected.

3. Ina telephone exchange system, a subscribers cord circuit, 'a' source ot ringing current, a switchboard, a link circuit for extending a connection from said cord circuit to said switchboard, a'signaling device associated with the link circuit, means for con necting said source to the link circuit to operate, said signaling, device, means for causing the disconnection of said source,'a relay responsive" to .the ringing current to apply said disconnecting means, .an energizing winding therefor, a secondrelay con trolled by the ringing response relay, a contact associated with said second relay normally in series with the winding of saidrlnglng response; relay forming an 'lllltlal operating circuit for said ringing response relay, a contact associated with the ringing to saidswitchboard, a signaling device assoa disconnectionlofthe source;

' closing said maintainin cuit inefi'ectiveL ciated with the linkcircuit, means for con said signaling device, a relay in the 'link circuit controlled by theiringlng response rel'ay, andm'eans controlled th ereby to cause necting the source to the, link circuit, mean-sresponsive to thel ringing current to operate 5.,lnte'lephone ex changefsystem,asubscribers cord circuit, sourccflof ringing current, a, switchboarmfa link circuit for extending a connection from saidcord ci'r- 'cuit to-saidfswitchboard, means for connecting the ringing current to the link circuit, a,

relay responsive to the ringing current, 'a

second relay controlled-by theringing re:

sponse relay means for caus-ing the disconnection or the source and means controlled,

vjointly by the 'said ringing response relay and said second relay to apply said disco-n.

necting means. I t

6. In a telephone exchange system a subscribers cord circuit, a source of ringing I current, a switchboard,la link circuit for, ex-

tending a connection from said cord circuit to said switohboard,a signaling device associated with the link circuit, means: for 'connecting said ringing current to the link circuit to operate said signaling device, means for causmg the disconnection of sa d source, a relay responsive to'the ringing curs.

rent to apply said disconnecting means, a

second relay .controlled by'the' ringing responserelay, an initial operating circuit for said ringing response relay, controlled by said second relay, a maintaining circuit 'for said ringingresponse relay, and means .for i g circuit before said initial operating circuit is. opened.

A In telephone y t m, a tru k 106" i circuit, 'means vfor establishing a connection therewith, a signaling circuit closed by the establishment of said connection, signal'cur rent responsive means actuated in response to-the closure of said circuit, arelay' alnd a' signaling device operated in response to the actuation ofsaid signal current responsive means, and means controlled'jointlyby said signal currentresponsive means and said relay-for rendering said signaling circuit in- @EQCCIVG. i

8; 'In a telephone exchange system, a subscribers line, a'trunk line, means'for estab llshing a'connect'ion therebetween, a signal? ing circuit closed by the establishment of said connection, signaling currentresponsive means actuated in response'to the closure of said circuit, a direct'current bridge, a relay energized by the actuation of saidv signal. cur- :rent responsivemeans' for connecting said, bridge acrosssald signaling circuit, a lock- 111g circuit for said relay completed in response to actuation thereofto maintain said bridge connected, and means controlled by,

said bridge for rendering said signaling cirI-j 9. In a telephone exchange system, asubscribers line, a trunk line, means for establishing aconnection therebetween, a ringing circuit closed by the establishment of said connection, a'relay in the trunk line actuated in response to the closure of said circuit, a -second relay, a signal actuated in response to the operation ofsaid first mentioned relay, and means controlled jointly by said first mentioned and said second relay for rendering said ringing circuit ineffective.

10. In a telephone exchange system, a trunk circuit, impedances in said trunk cir- L cuit, means for establishing a connection with said trunk circuit, means for establishing a signaling circuit by the establishment of said connection, signaling current responsive means actuated in response to the closure of said circuit for changing the impedance of said trunk circuit, a direct current bridge for said trunk circuit, a relay controlled by said signaling current responsive meansfor connecting said bridge across said trunk, and means controlled by the change in impedance of said trunk and-the connectionof said bridge for rendering the signaling circuit ineflective.

In Witness whereof, I hereunto subscribe my name this 16th day of November A. D.,

LOUIS A. MORTIMER. 

